1. Field of the Invention
The invention concerns paper sizing agents on the basis of acid group-containing polymers from unsaturated hydrocarbons of an olefinic character (so-called acid hydrocarbon resins), either alone or in a mixture with co-polymers from unsaturated polycarboxylic acid units with .alpha.-olefins or vinyl monomers, possibly in mixture with other resins, as well as the sizing of paper with these sizing agents.
2. Description of the Prior Art
It is known from DT-OS No. 24 02 926 (German Patent Disclosure), that resin sizings, based upon colophonium resin can be used, if one modifies the colophonium resin by reacting it with an .alpha.-.beta.-unsaturated carboxylic acid or its anhydride. This "reinforced" colophonium can be extended by the addition of neutral hydrocarbon resins. This resin mixture is recommended, in combination with a volatile base in the form of aqueous dispersions, which require the addition of a protective colloid, such as casein, as a paper sizing agent.
It is further known that solutions or dispersions of co-polymers from carboxylic acids, or their anhydrides with olefins and their conversion products with basic compounds are suitable for paper sizing.
A high degree of sizing can be imparted to the paper with these co-polymers, however the water resistance of papers, sized in this manner, remains low.
These "synthetic" sizing agents, corresponding to the state-of-the-art, also lead--when sizing in-mass pre-sized paper, such as primarily applied in practice--to poorer sizing results than in surface sizing of unsized paper which, for technical reasons, however, is not generally available.